The Root Bridges of Cherrapunji refer to bridges that are woven from the roots of living rubber trees in the Cherrapunji rainforests of Meghalaya, India. Some of them are more than a hundred feet long, grow over decades and withstand the weight of fifty people. Not only are they environmentally friendly, the bridges are also quite utilitarian since the roots grow stronger over their lifespan. For more info, check out this BBC video.